# Link a subtype and a temporal role

## Intent

I want to join subtype facts with supertype facts without turning a role into a permanent type.

Branch and company facts join.

## Wrong form and why it stays silent

```law title="Incorrect form"
entity Branch; // связь с Company потеряна
```

An explicit subtype is compatible with a Company slot. Role Applicant declares the role name; it itself assigns no participant. In the working example the temporal role is presented by relation applicant.

## Correct form

```law
language "law.core" version "0.2";
package recipes.g.r08 version "0.1.0";
namespace "urn:recipe:g-concepts:08";

entity Company;
entity Branch : Company;
role Applicant for Company;
relation branch(b: Branch);
relation registered(c: Company);
relation applicant(c: Company);
relation eligible(b: Branch);
rule Qualify strict { for b: Branch; when branch(b) and registered(b) and applicant(b); then eligible(b); }
```

## Frozen execution scene

| Facts on 13.09.2026 | Question | Answer |
|---|---|---|
| one branch, three facts | `truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")))` | `truth_status == TRUE_ONLY;` / `COMPUTED` |
| role not given | `truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")))` | `truth_status == NEITHER;` / `COMPUTED` |
| different entities | `truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")))` | `truth_status == NEITHER;` / `COMPUTED` |

```law
test "one branch with three facts qualifies" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }
        assert branch(entity_ref("urn:recipe:g-concepts:08:p")); assert registered(entity_ref("urn:recipe:g-concepts:08:p")); assert applicant(entity_ref("urn:recipe:g-concepts:08:p"));
    }
    evaluate truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")));
    expect truth_status == TRUE_ONLY;
    expect evaluation_status == COMPUTED;
}
```

```law
test "missing role stays unknown" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }
        assert branch(entity_ref("urn:recipe:g-concepts:08:p")); assert registered(entity_ref("urn:recipe:g-concepts:08:p"));
    }
    evaluate truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
}
```

```law
test "different entities stay unlinked" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }
        assert branch(entity_ref("urn:recipe:g-concepts:08:p")); assert registered(entity_ref("urn:recipe:g-concepts:08:q")); assert applicant(entity_ref("urn:recipe:g-concepts:08:p"));
    }
    evaluate truth(eligible(entity_ref("urn:recipe:g-concepts:08:p")));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
}
```

## Counterfactual

Mutation `entity Branch : Company;` → `entity Branch;`: LDC-E2104.

## Boundary

A role declaration is sugar for a standard role, not a subtype and not membership. Full has_role with legal_context/during is needed when the role itself participates in a cross-context model.